The present invention pertains to the disinfecting of contact lenses, and more specifically to an improved disinfecting unit for the thermal disinfecting of lenses disposed within a lens case along with a quantity of disinfecting solution, wherein the lens case and the enclosed solution are heated to a specified temperature.
In recent years, soft contact lenses have been developed as an alternative to hard contact lenses, which due to their hardness often irritate the eye, and thus could not be used by many individuals. Soft contact lenses are fabricated from a hydrophilic plastic material, that is a porous plastic material that when dry is firm and can be formed to the desired lens curvature, but will absorb water and become soft and pliable. As can be appreciated, the soft pliable nature of these lenses permit the wearer to adapt more readily to the presence of the lenses on the cornea of the eye.
While hard contact lenses required periodic cleaning and disinfecting, the disinfecting of soft lenses is critical and it is recommended that the lenses be disinfected on a daily basis. The need for frequent disinfecting results due to the porous nature of the plastic material, which provides a medium for bacteria growth that can lead to serious eye infections.
Several disinfecting methods have been developed and employed with success in conjunction with soft lenses. One of the most popular methods involves the disposition of the lenses in a saline or disinfecting solution, and the heating of this solution to a temperature sufficient to destroy any bacteria that might be present. A second method involves the employment of a chemical process to destroy the bacteria. As to the thermal or heat disinfecting methods, this can be accomplished by either "wet heat" process or a more recently developed "dry heat" process; the latter being the process to which the present invention relates. With respect to "wet heat" processes, the lenses are placed in a case which includes a disinfecting solution, and the case is then placed in a second vessel containing a quantity of water which is brought to a boil, with the heat being transferred to the lens case by way of the surrounding water. With a "dry heat" method of sterilization, the lenses are disposed within a lens case and the disinfecting solution added to the case. The case is then placed in surface-to-surface contact with the heater unit, such that direct application of heat is attained from the heater unit to the lens case and the sterilization solution contained therein. Often, the lens case is a sealed vessel which permits heating of the solution above the boiling point, if desired.
The present invention pertains to a disinfecting unit adapted for use in the "dry heat" type of process. In this regard, the present invention has as its main object the provision of an improved disinfecting unit design which is adapted for use with relatively flat lens cases in which the lenses are immersed in a quantity of disinfecting solution. Another object of the present invention is the provision of a novel arrangement for the internal heater mechanism for such a unit, which assures that the support surface and correspondingly the lens case resting thereon are raised to the desired disinfecting temperature, before the heating element is de-energized via a conventional thermostatic device.
The exact manner in which the above-noted objects and other objects of the invention are achieved will become apparent from the following detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings wherein like reference numerals indicate coresponding parts throughout the various views.